In the production of fluids from wells, it is a common practice to utilize submergible pumping equipment to bring well liquids to the surface at a desired rate and one type of pumping unit now in use is the submergible pump which is lowered into the well beneath the surface of the liquid and which is powered by an electric motor. The pump and motor are lowered and removed from the well by a suspension cable having both weight supporting and electrical power conducting capabilities. After the pumping unit and motor are properly located within the well, it is necessary that the assembly be locked or anchored in such location to prevent displacement thereof during the pumping operation. Not only is the pumping equipment and its locking assembly subjected to the pressure forces tending to displace the same from the well in an axial or longitudinal direction but because the pump is driven by the rotating shaft of the electric motor, said equipment and its locking assembly is also subjected to the torque or rotative forces developed and transmitted thereto by said rotating motor shaft. This torque force tends to rotate the locking assembly and pumping equipment which may result in damage to these elements.
Various locking assemblies for submergible pumping equipment have been in use and although such prior assemblies usually provide adequate locking against axial or longitudinal displacement, none of said prior assemblies include a simple and practical positive means for locking or anchoring the equipment against rotative movement. Examples of prior attempts to effect locking against rotative movement are disclosed in the U.S. Pat. Nos. 4,121,659 to Taylor and 4,171,934 to Zehren. The Taylor patent recognizes that rotation of the assembly should be prevented but relies on the frictional grip of sealing members to "resist rotation" of said assembly by the pump. Obviously, such frictional contact of resilient sealing material is insufficient to assure that the assembly will not rotate under the torque forces. The Zehren patent also recognizes the need for preventing rotation of the locking assembly and provides a lock for preventing rotation of the discharge head by means of a complex arrangement which expands locking lugs into recesses; also the outer member of the discharge head has a second lock comprising interengaged teeth elements. Once engaged, the locking lugs cannot be released without removing the entire pumping unit and removal can be accomplished through the shearing of pins. Other prior patents, such as the U.S. Pat. No. to O'Rourke, 3,853,430 illustrate locking assemblies but suggest no simple solution to preventing rotation due to torque forces.